The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Clutches for motor vehicle powertrains provide a frictional, variable torque transmitting coupling between the vehicle prime mover and the transmission. Because of this function, significant heat may be developed in the clutch plates, especially if the vehicle is driven hard or the clutch is operated partially engaged for any period of time. Such worst case operating scenarios, which much be addressed, typically result in a clutch designs that comprehend larger clutch plates, more numerous clutch plates, a larger flywheel, more robust clutch materials (facings) and other design approaches. Such larger clutch components are not solely driven by higher torque requirements but also by operating temperature and heat dissipation considerations. That is, larger clutch plates and faces, while carrying less torque and therefore generating less heat per square unit of measure than smaller clutches, also have the capability of dissipating more heat, more rapidly than smaller clutches, not only because of their larger size but also the larger size of their housings which, in turn, increases the rate at which heat can be transferred to the ambient.
Increasing the size of a clutch, while thus clearly advantageous from heat generation and dissipation viewpoints, is not an engineering solution without serious consequences. First of all, it clearly adversely affects the weight of the clutch and housing and thus the overall weight of the vehicle. In an age when every ounce of removed vehicle weight is considered a small victory, adding several ounces or pounds to a clutch assembly requires the most sound justification. Second of all, increased clutch and housing size affects not only the size of the overall powertrain but also its packaging. Whereas a smaller clutch and housing will permit enhanced packaging flexibility, a larger clutch may create additional constraints. Last of all, increasing the weight of the rotating powertrain components will have a small but tangible effect on the fuel consumption of the associated vehicle as well as its performance.
From the foregoing, it is apparent that approaches to clutch heat dissipation other than simply increasing the size of the clutch may provide better solutions with fewer compromises. The present invention addresses this problem.